The present invention relates to Spanner Wrenches and more particularly to spanner wrenches in which the span between the drive pins is adjustable.
In the prior art, there are many and various spanner wrenches.
Specifically, there are several adjustable spanner wrenches which provide an adjustable span between slots in an article to be turned.
U.S. Pat. No. 2,803,981, shows a spanner wrench in which a pivotally mounted bar at the base of the wrench has a slot wherein drive pins are mounted. The span between the drive pins is adjusted by moving the drive pins within the slots and the drive pins are tightened at a desired position by nuts mounted on a threaded upper portion of the drive pin. The spanner wrench according to the patent has the disadvantage that as the tightening nuts become loosened, the drive pins slide along the slots and it is difficult to maintain the proper spacing. Also, with wear, the drive pins would tend to slide in the slots, thus limiting the usefulness of the wrench. Further, the range of adjustment is limited to twice the length of the slot.
Another adjustable spanner wrench is shown in U.S. Pat. No. 3,010,347, in which the L-shaped members are attached to the movable and fixed jaws of a cresent wrench. Adjustment of spacing is made by opening or closing the jaws of the Cresent Wrench. While this patent shows a device which has a certain amount of flexibility, the handle of the Cresent Wrench must be relatively at right angle to the axis about which the article is to be turned. In many applications where space is limited such a wrench would not be useable.
Another adjustable spanner wrench in the prior art is shown in U.S. Pat. No. 3,731,560, which shows a wrench having a Y-shaped handle wherein each of the branches of the Y has a hole therein to accept a disk which is rotatbly mounted in the hole and wherein the disk has a drive pin mounted near the edge of one face thereof. An adjustable spanner wrench according to this patent is limited to a range of adjustment which is equal to twice the diameter of the disks mounted in the holes in the Y-shaped handle. Also, as above, the handle must be at right angle to the article which is to be turned.